The University of Southampton
University of Southampton Institutional Repository
Warning ePrints Soton is experiencing an issue with some file downloads not being available. We are working hard to fix this. Please bear with us.

Infrared deflectometry for slope deformation measurements

Infrared deflectometry for slope deformation measurements
Infrared deflectometry for slope deformation measurements
This paper presents an implementation of deflectometry in the infrared spectrum. Deflectometry consists in recording the specular image of a reference grid pattern onto the mirror-like surface of a test specimen. This technique has two main advantages, high sensitivity and direct measurement of surface slopes, which in the case of thin plate bending is only one spatial differentiation away from surface strains. The objective of imaging in the infrared spectrum is to mitigate the main limitation of deflectometry in the visible spectrum, which is to require an extremely smooth surface to provide dominant specular reflection. This paper explores IR deflectometry for the first time for deformation measurements. Two different infrared cameras were assessed for use in IR deflectometry, a short wave quantum detector one, and a long wave microbolometer (MB) array one. Different materials of varying surface roughness were imaged and it was verified that the Rayleigh criterion was appropriate to determine whether IR deflectometry was feasible on a given surface. With the MB camera, most off-the-shelf material surfaces proved reflective enough to perform IR deflectometry.
Finally, several bending tests were performed on aluminium plates and the deformation fields were shown to compare remarkably well with finite element simulations. The experimental data were then used in the Virtual Fields Method (VFM) and the elastic stiffness components of aluminium were retrieved with excellent accuracy, further validating IR deflectometry.
Deflectometry, Infrared imaging
0014-4851
1187-1202
Toniuc, Horea
aebb4d2d-261b-45de-93c3-d265bfc284a0
Pierron, Fabrice
a1fb4a70-6f34-4625-bc23-fcb6996b79b4
Toniuc, Horea
aebb4d2d-261b-45de-93c3-d265bfc284a0
Pierron, Fabrice
a1fb4a70-6f34-4625-bc23-fcb6996b79b4

Toniuc, Horea and Pierron, Fabrice (2019) Infrared deflectometry for slope deformation measurements. Experimental Mechanics, 59 (2), 1187-1202. (doi:10.1007/s11340-019-00480-9).

Record type: Article

Abstract

This paper presents an implementation of deflectometry in the infrared spectrum. Deflectometry consists in recording the specular image of a reference grid pattern onto the mirror-like surface of a test specimen. This technique has two main advantages, high sensitivity and direct measurement of surface slopes, which in the case of thin plate bending is only one spatial differentiation away from surface strains. The objective of imaging in the infrared spectrum is to mitigate the main limitation of deflectometry in the visible spectrum, which is to require an extremely smooth surface to provide dominant specular reflection. This paper explores IR deflectometry for the first time for deformation measurements. Two different infrared cameras were assessed for use in IR deflectometry, a short wave quantum detector one, and a long wave microbolometer (MB) array one. Different materials of varying surface roughness were imaged and it was verified that the Rayleigh criterion was appropriate to determine whether IR deflectometry was feasible on a given surface. With the MB camera, most off-the-shelf material surfaces proved reflective enough to perform IR deflectometry.
Finally, several bending tests were performed on aluminium plates and the deformation fields were shown to compare remarkably well with finite element simulations. The experimental data were then used in the Virtual Fields Method (VFM) and the elastic stiffness components of aluminium were retrieved with excellent accuracy, further validating IR deflectometry.

Text
IR_deflectometry_R1_v3 - Accepted Manuscript
Download (8MB)
Text
Toniuc-Pierron 2019 Article Infrared Deflectometry For Slope D - Version of Record
Available under License Creative Commons Attribution.
Download (5MB)

More information

Accepted/In Press date: 3 February 2019
e-pub ahead of print date: 17 July 2019
Published date: 2019
Keywords: Deflectometry, Infrared imaging

Identifiers

Local EPrints ID: 428285
URI: http://eprints.soton.ac.uk/id/eprint/428285
ISSN: 0014-4851
PURE UUID: dc90fb1c-a6f0-4159-97b9-6b08cce52922
ORCID for Fabrice Pierron: ORCID iD orcid.org/0000-0003-2813-4994

Catalogue record

Date deposited: 20 Feb 2019 17:30
Last modified: 26 Nov 2021 05:32

Export record

Altmetrics

Contributors

Author: Horea Toniuc
Author: Fabrice Pierron ORCID iD

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×